Whenever used in this part the term “police force” includes among others, jailors, turnkeys, guards, matrons, lunas, and cooks employed in any county jail.

This section shall apply only to county employees in service on December 31, 1927, who, if members of the police force on that date, would be or would have been entitled to membership in one of the pension systems provided for by this part, and who shall have applied to the board of trustees of the pension system in which they are entitled to claim membership under this section before January 1, 1932. No employee who complies with this section shall be held to have waived the employee’s right to membership in any such system by reason of the employee’s having joined or become a member of the employees’ retirement system after December 31, 1927, but the membership in the system shall cease when the person becomes a member of any pension system.

The board of trustees shall pass upon the applications and determine whether or not the applicants are entitled to membership under this section.